How can I monitor 2 vpn channels in Cisco, with notification of their fall?

Question

Notifications

Good afternoon, I would like to set up on 2 Ciscos, each of which has 2 backup providers, both of them are connected to each other by vpn, OSPF is configured, cost is registered on both tunnels, one is more priority and the second is reserved. It is necessary to set up monitoring of both channels, so that in case of problems with one of them for any reason, one of which may be, the provider cuts GRE, a notification about the problem channel comes. The first step is to make it possible to check the local resource of another router through the tunnels, according to the current scheme, because one is backup, and the second main one can only be checked through the main one, if checking through the backup resources is not available. And then set up monitoring and options for sending notifications. Tell me how this can be implemented?

Answer 1

Good afternoon. Dig towards IP SLA

Answer 2

All this is good, but I would like to understand how I can monitor 2 tunnels at the same time, as I wrote at the moment with such settings, both tunnels are in the up state, but since the route is registered only through the main one, then if you check the local address inside the tunnels, the main check will pass, but there is no backup, because it is not involved, how to fix it, despite the fact that you still need to leave one backup, and the 2nd main one?